Security paper is used in the production of printed items that represent sufficient value to make them a temptation to forgery. In the past, security paper has been produced from high quality cellulosic papers. Usually these security papers include specific features or materials that are readily identifiable but very difficult to reproduce. The manufacture of many security papers involves spreading or distributing minor amounts of the identifiable materials in the paper pulp during the wet-consolidation of the pulp on a paper-making machine. Among the special identifying materials that have been included in security papers are fibrous material in various shapes, colored particles, silk threads, particles containing certain inorganic substances, fluorescent fibers, metallized fibers, metal wires, various non-fibrous thermoplastic materials and the like. Such identifying materials have been distributed throughout the security paper or have been contained in a layer near the mid-plane of the paper. Watermarking also has been used to provide special designs on the paper. Such security papers have found use in bank notes, paper currency, stock certificates, bonds, legal documents, passports, visas, travel tickets and the like.
Although nonwoven materials or synthetic organic fibers have been long known as possible substitutes for paper or cloth in many uses, such nonwovens have not found use in security papers, apparently because of the specific requirements of security papers.
Applicant has now found a specific nonwoven fibrous synthetic organic material that can be processed into a strong, durable, high quality security paper.